I've used a Visa gift card from my local mall for my past two trips. The first time, I ordered it online and got it personalized. The fee was like $5-$6. After the fact, I found out that you could get one at the mall's service desk for only a $1.50 fee, so I did that for the second trip. But it wasn't personaized. It just came with a generic name and message.
(The name line said "Simon Mall", and I had one CM refer to me as Simon, and another as Mr. Mall.... And a third was confused for a moment because the name in my signature didn't match the name ont he front...)
But anyway, I much preferred using the gift card over traveller's checks or cash. I saved up the money and bought the card when I had enough, and then I didn't have to worry about that part of my trip anymore. And the card is accepted in 98% of places at WDW. Anywhere you can use a credit card you can use it.
One tip: If you have to return something, be prepared for it to take 3-5 days for the money to appear back on the card. Toward the end of the vacation, the card was rejected. I thought I'd just gone through the money faster than I thought, when in fact a return I'd made hadn't credited back yet.
Another option for you might be to get one of the new Disney Gift Cards that can be used at the parks, the Disney Stores and online. I don't think there's a fee involved, and the funds never expire like the Visa gift cards do. Plus, you can reload the gift card with more money. (Currently only at the locations that sell the cards, but I'm sure they're working on adding online ability). So if you buy one at your local Disney Store, you could conceivably keep adding to it every few weeks as a way of saving for your trip.
There's info at
www.disneygiftcard.com
-Rob